Water injection for ejection performance boost



May 18, 1965 E. J. BARAKAUSKAS WATER INJECTION FOR EJECTION PERFORMANCEBOOST Filed Jan. 25, 1963 CONTROL F/G. Z

EB E L BQ I OF WATER TIME INVENTOR Edward J; Bamlrauskaa B WM/ FIG. 3'

ATTORNEY United States Patent 3,183,904 WATER INJECTION FOR EJECTIONPERFQRMANCE BOOST Edward J. Barakauskas, Saratoga, Calif., assignor, bymesne assignments, to the United States of America as represented by theSecretary of the Navy Filed Jan. 25, 1963, Ser. No. 254,825

1 Claim. (Cl. 124-41) The present invention relates to a method andapparatus for launching missiles and is particularly directed to thattype missile which is launched from an underwater position.

At the present, the ejection system for launching the underwater missileis limited to a keel depth range of feet from the nominal launch depth.With a fixed pressure air system, the same air flow rates are utilizedindependent of the keel depth of the submarine. At the shallow limit ofthe keel depth range, the crushing loads on the missile after missileexit limits the amount of air that can be used for ejection. As the keeldepth is increased, the missile velocity obtained from that amount ofair decreases. At 20 feet greater depth the velocity decreases to theminimum within the specified missile velocity criteria. If the depth isincreased further, the velocity falls below the specified velocityrange.

A significant improvement in missile launching can be achieved if therange limits for launching can be opened up to :20 feet from the nominalkeel depth because the keel depth is very difiicult to control as theship is hovering during the launching process.

Previous approaches to increasing the keel depth range have beendirected towards methods of decreasing the exit pressure at the shallowdepths. In such prior systems suflicient air is provided in the launchflask to launch at the deep depths. When the submarine is at the shallowlimit of the keel depth band, means are provided to decrease the exitpressure to alleviate the missile pressure loadings. Of several methodsthe most feasible is to close the air valve while the missile is movingup the launch tube and thus limit the air entering the tube and therebythe exit pressure. Hardware for accomplishing this function has beenfound to be feasible by virtue of preliminary operational tests. Such asystem involves a large amount of hardware and is subject to abortingmissile launches in the event of a malfunction.

It is an object of the present invention to operate the compressed airejection system at pressures which are compatible with the missilepressure loadings at the shallow depth limits when the launching is atthe :20 feet keel depth range and to inject additional energy into thelaunch tube during launchings at greater depth limits.

It is a still further object of the present invention to inject,simultaneously with the compressed air, means of increasing thetemperature within the launch tube to provide the additional energynecessary to launch the missile from the greater keel depth.

It is a still further object of the present invention to provideadditional energy during the launching movement in a form which due tothe temperature drop caused by the expansion of the compressed air willproduce a freezing action on water injected therein and in freezing suchwater will liberate suificient heat to provide energy for increasing thelinear speed of the missile.

It is a still further object of the present invention to provide anapparatus including means for injecting compressed air and water intothe launching tube at a zone or level below the missile, the subsequentexpansion of the compressed air therein causing a drop in temperaturesufficient to freeze the water, the freezing of the water liberatingheat to provide the additional energy.

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Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of the launch tube and associated controlapparatus.

FIG. 2 is a diagrammatic view of the same apparatus showing a differentcontrol arrangement, and

FIG. 3 is a graph indicating the drop in temperature plotted againsttime.

Referring particularly to FIGS. 1 and 2 wherein like reference numbersdenote like parts throughout theseveral views, a launch tube 5 houses amissile 6. A source of compressed air 7 is connected through pipe 8 tothe launch tube 5 at a point below the missile. A source of water 9 isconnected by pipe 11 to the tube and by pipe 12 to the source ofcompressed air 7.

A valve 13 located in the air line 8 controls the flow of air from thesource 7 to the tube 5, While a valve 14 located in the water linebetween the water source and the air source controls the injection. ofthe water into the launch tube. These valves are connected to a controlmechanism 18 in a manner to be operated simultaneously at the time oflaunching of the missile, when the launching takes place at the deepdepth. When at shallow depth, the valve 14 is closed and the water isnot drawn into the tube. This tends to compensate for the difference inkeel depth approximately :20 feet. Referring particularly to FIG. 2 asimilar apparatus is shown with the difference that the line 16connecting the source of water with the source of air is connected intothe air line on the launch tube side at the point 17. The water is theninjected into the launch tube by the pressure differential between thepipe and the launch tube. Here again, the valve 14 is used to shut offthe water for shallow launch and is opened for a deep launch.

The graph shown in FIG. 3 is illustrative of the drop in temperature.

During the latter half of the ejection cycle, the air in the launch tubegets very cold because the air in the launch tube expands doing work andthe air coming in from the launch flask is very cold since it hasexpanded in the flask from a high to a low pressure. The injection ofwater during the launch cycle will have no effect until the airtemperature drops below the freezing point of water. After thisoccurrence, the water freezes liberating heat, and prevents thetemperature from dropping as far as in the waterless launch situation.By adding energy the temperature and pressure of the air is increased,increasing the missile acceleration and velocity. An increase of missilevelocity of 7 fps. has been observed when water is present. This issuflicient to extend the keel depth range for launching by the desired20 feet.

What is claimed is:

A missile launching apparatus for increasing the energy of launchingcomprising:

a launching tube closed at its bottom end and having a missile supportedin said tube and spaced from said bottom end;

a compressed air delivery tube secured. to and communicating with thetube adjacent the bottom end;

a tank delivering compressed air to said delivery tube;

a valve in said delivery tube between said tank and said launching tubeto control the delivery of said compressed air to the launching tube;

a tank containing water;

a water delivery tube connected to said launching tube directly belowthe bottom end of said missile;

a tube connecting said water tank with said compressed air tank;

' 3 a valve in said connecting tube to control the passage of compressedair from said compressed air tank to said water tank; a mechanismcontrolling the actuation of each of said valves; whereby compressed airand water are delivered to the space at the bottom of the launching tubeas desired, the resultant movement of the missile in the tube increasingthe volume of the closed chamber causing an expansion of the airresulting in atem- 10 consequent freezing of the water liberating thelatent heat of fusion, the energy of said liberated heat adding to theenergy of launching.

References Cited by the Examiner UNITED STATES PATENTS 1,526,256 2/25Techel 114--238 2,989,899 6/61 Siegel et al. 89--1.7 3,088,377 5/63Siegel 89--1.7

BENJAMIN A. BORCHELT, Primary Examiner.

